In the current state of the prior art, the thermic protection films of such structures are constituted by composites with organic, organo-metallic or mineral binders able to include reinforcements made up of powders, fibers, organic tissues or minerals. Under the action of the hot gases, the ablatable material undergoes the pyrolysis phenomenon. This pyrolysis is accompanied by a degradation of the carbonated or organo-silica chain of the binder which renders the slag fragile and brittle inside the mass. So as to mitigate this fragility, the thermic protection layer is currently reinforced according to various techniques.
In fact, for an ablatable material of this type subjected to erosion by hot gases and to vibrations, it is known that ablation is reduced when the material is reinforced. The reinforcement embedded in the nonconducting material may be metallic, woven or fibrous.
The patent FR-A-2.569.237 describes such a reinforced thermic protection device and the corresponding production method for thermically protecting walls skirted by gas flow veins, such as ram jet engine chambers.
The advantage of this prior patent was to make it possible to embody a flexible protection film, possibly made of silicon, reinforced by a reinforcement orientated with respect to the flow of gases, which provides good resistance to ablation and tearings provoked by the vibrations due to the functioning of the engine.
So as to improve the mechanical behaviour of a structure after pyrolysis of the binder, it is necessary to reinforce the thermic protection so that after pyrolysis of the matrix for the entire thickness of said protection, the residual material obtained constitutes a nonconducting, non-fissured and non-crackable casing protecting the external structure whilst the engine is functioning.
One of the most advantageous ways to structure a matrix is to embody three-dimensional structurings by means winding the wire in a radial direction and depositing the wire longitudinally on a mandrel provided with picots. The matrix is normally brought by injecting non-charged liquid resin into the meshwork of the prepared structure.
However, this technique has the drawback of setting the diameter of the thermic protection since it uses circumferential wires unable to deform when pressurizing the chamber, especially initially when the accelerator integrated in the chamber is functioning, whereas the metallic structure shall deform, which will induce rupture of the thermic protection by these circumferential wires and risks rupturing the glued link.